434 NOURISHMENT FOR A HEALTHY ADULT. 



2. Inorganic matters as integral parts of all of the tissues, without 

 which their structure could not be formed. These substances are present 

 in sufficient amount in all the usual articles of diet, so that it is unneces- 

 sary to supply them separately (as the nutrition of animals shows). 

 Increase in the supply of salt causes increase in the consumption of 

 water, and this in turn causes increase of nitrogenous decomposition in 

 the body. Withdrawal of certain necessary salts causes disturbances in 

 the nutrition of the tissues containing them. Thus, the use of food free 

 from calcium is followed by disturbance in normal bone-formation ; 

 withholding common salt causes albuminuria. The body absorbs the 

 iron required for the formation of blood in part in the form of complex 

 organic compounds from the vegetable and animal kingdoms, but in 

 part also in an inorganic form; phosphorus principally from proteids 

 containing phosphorus. The alkaline salts derived from vegetable food 

 serve to neutralize the sulphuric acid formed by oxidation of the sulphur 

 of the proteids. Food that has been artificially deprived of all salts 

 causes rapid death in animals by acid intoxication. 



Only as a matter of necessity does man occasionally resort to the use of 

 considerable amounts of inorganic matter in order to obtain the organic 

 nutrient material mixed with it, as A. v. Humboldt relates of the inhabitants 

 along the shores of the Orinoco and the Meta, and who, in times of scarcity, 

 when the catch of fish is low, are compelled to eat a certain kind of rich clay, 

 containing an abundance of infusoria. 



3. At least one animal or vegetable proteid. The albuminates are 

 utilized to replace the consumed nitrogenous tissues, particularly the 

 muscles. In addition, they are used as sources of energy and heat. The 

 latter function of albuminous food can be fulfilled by non-nitrogenous 

 food; the first, however, can not. The albuminates contain from 15 to 

 1 8 per cent, of nitrogen. 



Different tissues of the body contain proteids in the following proportions: 

 Blood 20.56 per cent., muscles 19.9 per cent., liver 11.74 per cent., brain 8.63 

 per cent., blood-plasma 9.0 per cent., milk 3.8 per cent., lymph 2.4 per cent. 

 According to Pfluger and Bohland a growing youth weighing 62 kilos decom- 

 poses 89.9 grams of albumin daily. 



It is a remarkable fact that asparagin a nitrogenous amido-body, which 

 is formed in sprouting plants from albumin and under certain circumstances 

 may be again transformed into this in the plant combined with gelatin is 

 capable of replacing the albumin of the food. Asparagin alone is capable 

 (only in herbivora) of diminishing the decomposition of albumin. Salts of 

 ammonia, glycocoll, sarcosin and benzamid increase the destruction of proteid. 



4. At least one form of fat or digestible carbohydrate. These serve 

 principally for the replacement of the decomposed fat and non-nitrog- 

 enous constituents of the body. On account of the large amount 

 of carbon they contain, they are, through their oxidation, the chief 

 sources of heat-production. Fats and carbohydrates can replace each 

 other in the diet in reciprocal amounts corresponding to the quantity of 

 heat that they are able to produce by their combustion in the body. 

 In the same way, the portion of the albumin of the food that does not 

 serve for the restoration of the tissues can be replaced by equivalent 

 amounts of fat or carbohydrates. In this connection 100 parts of fat 

 are equivalent to 256 of grape-sugar, 243 of milk-sugar, 234 of cane- 

 sugar, 221 of dry starch. In general the same amounts correspond to 

 227 parts of carbohydrate, as well as to 227 of albumin. 



